Filling of joint boxes for electric cables



Nov. 6, 1928. 1,690,658

. A. E. WILSON FILLING OF JOINT BOXES FOR ELECTRIC CABLES Original Filed June 18, '1925 Patented N (W. i 1928.

PATEN LQ F C -i v ALFRED Emmwmw, or BROMLEYyENGLAND.

FILLING onJom'rnoxns FoR E'LEcTmc CABLES! t Originalabirliation fflled iruneis, 1925, Serial up. 38,116, aria inmost Britain "This application; is divisional from the present applicants application for, Letters Patent ofthe United States of Ameni ce ,Serial No.'38,116,- filed June18, 1925,. Theginventionrelatcs to the filling of joint boxes for electrie cables m dlms particulaiyrefen ence .to gomtboxes for super-tension cables.

, It is iinportahtthat the jOint boxes for such cablesshull-be free-from acuous spaces orv spaces containing a r at less thangatmos- 7 Boxes madewith domes toentra peh huve been filled with hot compound and spaces left after the cont-rnction ;jof the compound j on cooling have been filled with furthersupply of eompohnd' but such a smeth od involves the.

expenditure offconsiclerable time an clj one and it is practieally impossible ,to avoid the presence of smallspaces or cooling cones which, when tl 1e-;hox and its contents '2 1re"fi nally cool, conte-inair jat less than atmospherie pressures. M H T e t ccordi t the P e n 3 ventioniconlsists in fillingthebox with co a" pound;undergpressure in such e, wayth at when the box -end its contained joints are m 'eamth .or]atmospheric-ftemperature, ,t'l'iere are no svecuous spacesor spaces at less tha nfa t-i mospheric pressure, zillspaoes notfilletl with t the compound preferably beinget A pressure greater'than that of the atmos heref s Thecon ipound nseclffor, filhn 1])If8f817: ablyvof such :t natm ethatitfcan he forced in uncle'npressure-whilst cold. fFor example, itmay be e resinioil. It is not necessa ythat the entire pi'ooessof fillihglthe ,boii sh ll "he carried out under pressure and preferably the hox is first partially fillcd with heated compound by Qpourin g1 the cempounclfin ehd then the filling operat on isfcon pleted fiorcin'g I cold fluid fcsmpou d-ineusr 1 sure Theholesor peningsthro'l gh w i h the compoundjenters I and, leeires the loo); he

I p arranged in such g 'wy thzit they" oz'm'fbe closed on sealedwhilsttheeolnpounclis' uht lei' pressu -i: 1; g] The impr vcgl I method may 1 be carried out in rvzjtriousways '51 ml by zmy suitablelappsrzttus but preferably detachable fittings are provided for attachment to holes" crowning-s in; the. ,boxl. These holes pr openings ma be s eh 11 i a e usu y pro ided i o 'b d h mhei h tnt ex cel ql rthe lane 12'? e. 'hiinarv' 'i in, ant ore era P 11 1 s. 11 f ty prises a chamber open at the bottom antlerrangecl so that it canbe clamped clown pressure-tighteround the hole, say, by a yoke oi stirrup. I 'llhe holes are provided with screw plugs which are hollow and ilorinedwith lat el'al openings'so that when they m'e Ipartly unscrewed, the con'ipound can pass through them from or intothechamben Each fitting is providecl'with ineens such for 'ihstencefas a box spanneno'r' key, whereby the plugs can be screwed "down to close the op'ehings end thus seal th'e box whilst the compound is under pressure. The spindles "ofthe spam ners or keys pass o utnt the tops of the-chem"- hers through 'suitublelglmids, fThe 'd'} tachable fitting 'forthe entranoe hole is adapted to receive the hozz'le offa pump whichi'for instance, inztyscrew into an open- 7 ing at the side ofthe chamber; Alternatively thech'a nber of the pum l I The fitting forthe Vent for itselfmny form part of "the base ii thol'e is provicledjfwi'tl'i a; relie f vvaljve w ch closes a hole inthe side of the chambernd is 1101 11 2111 kept on its seating'jiby a weight or spri J a screw. f v r ,7

A convenient method of carrying oulfth e mention withthespy rutuscleserihedis as follows :+-Thc witht *i'ointetlfeuhles firsti filledns'fellas desiretlfwiththe eoinpouhl whose pressurecen; be regulated by means of v .2

usual, way; throughthe entrance hole at one fend off the oint box, the plug for that hole corr spo'ncli plug for the Vent hole emov d' or loosened. After this I After the com o nd, hes 'c'ooletl', the plugs are inserted I lfittingsztre'pla'ced inp'osition and' tlu npe'd downby their 'yokcs or st Zrups so as h'iiikeh pressure-ti ht j oint i the openingsfand 3 plugs. l, The] relief 'l e ofthe fitting over ithew ent oltienihg is pisted so th'atit will open whent-he desired pressure is attained and "cold but "still coinfpsi etively fluid col'npfoun'cl is forced by the pump into the fitting oventhe'entranee hole, through the loose plugin that hole and into I Ju1y 26, 1924. I niv'iq m I and this'applicationfl lfed' lly 7, 1926. Serial No. 107,526. r 5 i plug and the chamber of its fitting and through the relief valve. The extrusion of the compound through the relief valve is an indication that the box has been filled with the compound under the desired pressure and the spanners or keys are then operated, whilst the pressure is still on, to close the two plugs thus retaining pressure within the box. After this the yokes or stirrups canbe removed and the fittings detached leaving the joint box finished.

The improved method may be applied to any suitable form, of joint box but is particularly suited for application to any known form of metal oint box having domes formed in its upper portion and by such application it is possible to ensure that any air entrapped in the dome shall be under a pressure which, when the box is at earth or atmospheric temperature, is equal to or greater than atmospheric pressure. V r

In the accompanying drawings,

Figure 1 is an elevation partly in section showing one construction of joint box and detachable fittings suitable for use in carrying out the method according to this invention,

Figure 2 is a central vertical section through the fitting for the outlet or vent hole,

Figure 3 is an elevation of the same fitting viewed at right angles to Figure 1, and

Figure 4 is an elevation partly in section of the inlet fitting.

Figures 2, 3 and 4 are scale than Figure 1.

\Vith reference first to Figure 1 A is a metal joint box having an inlet or filling hole at A and a vent at A and also provided with air domes A and openings A and A which can be closed by screw plugs and washers A AT.

To the entrance or filling hole A a detachable fitting B can be clamped by means of a yoke B Through a. gland in this fitting passes a rod B having at its lower end a box spanner or key which engages with a squared end on the screwed plug A (Fig ure 4). This plug is hollow and provided with slots A so positioned that when the plug is partially unscrewed, communication is established between the interior of the detachable fitting B and the box A. The fitting B is provided with a screwed opening B to take the nozzle C of a pump C. In Figure 1 this pump C, is shown as provided with a screw-operated piston C worked by a handle C which is hollow and has one end threaded as at C so that when the pump is not in use the handle can be slipped over the screwed piston rod to protect it, the threaded portion G engaging with a screwed boss C on the cover.

The vent hole A is provided with a detachable fitting D shown in more detail in Figures 2 and 3. This fitting can be clamped drawn to a larger to the venthole A by means of a yoke D and has a rod D passing through a gland and provided at its lower end with a spanner or key for a screwed plug A fitting into the vent hole A This screwed plug A is hollow and provided with slots as at A so that when the plug israised by turning the rod D as shown in Figure 2, there is freecommunication between the box A and the interior of the fitting D. At the side of the fitting D is a screwed boss D fitted with a cap D containing a valve D which fits on a seating at the end of the hollow boss D The stem D of the valve D passes into a guide sleeve D having a screwed stem D and a coiled spring E is placed between the valve D and a collar on the guide sleeve D The valve D functions as a relief valve and the pressure at which it works can be adjusted by turning the screwed stem D After adjustment the stem D is covered by a cap D and this cap is kept in place by means of a plate D (Figure 3) so that the adjustment of the valve cannot be tampered with. The cap D is provided with a small outlet hole D (Figure 3) leading to a tray or catcher D 7 In operation the box containing the jointed cables is first preferably filled as full as may be desired with the compound previously heated so that it flows very easily. This may be done in any usual way through the entrance hole A before the fitting B is attached to it,

some or all of the plugs A A and A being loosened or removed. After this preliminary filling and preferably after the compound has cooled, the fittings B and D are attached to the inlet and vent holes respectively and clamped downso as to make pressure-ti ht joints, the plugs A? and A being raisec. The relief valve D is'adjusted so that it will open when the desired pressure is attained and cool but still comparatively fluid compound is forced by the pump G into the fitting B through the plug A into the box A. At any convenient stage in this process the plugs A and A are closed and the filling is continued until the compound is forced out through the vent hole plug A and the fittin D through the relief valve chamber or cap D. The extrusion of the compound through the hole D into the tray D is an indication that the box has been filled with the compound under the desired pressure and the rods D and B are then operated whilst the pressure is still on, to close the plugs A and A thus retaining the pressure within the box. The yokes or stirrups D and B can then be removed and the fittings detached, leaving the joint box finished. lVhen, as in the constructionillustrated and described by way of example, the joint box is furnished with air domes A it will be ob vious that any air entrapped in the domes during the final filling process may be left at a predetermined pressure which, when the box is at earth or atmospheric temperature, is equal to or greater than the atmospheric pressure. o n I What I claim as my invention anddesire'to secureby Letters Patent is '1. A method of 'fillinga joint box for electric cables consisting in filling the box through 'an'entrance hole with fluid compound under pressure until'said Compound extrudes through a variable relief vent in the box and then closing the entrance hole and the vent hole to seal the box while thecompound isstill under pressure I 2. A method of filling a joint box for electric cables consisting in filling the" box through an entrance holewith fluid compound under pressure until said compound extrudes through a relief vent in the box and then closing the entrance hole and the 'tri'c cables in which the box, after being par tially filled with heated compound and allowed to cool, is then completely filled by forc- 7 ing in cold fluid compound under pressure through an entrance hole until said cold compound extrudes through a variable relief vent in the box, and then closing the entrance hole and the vent to completely seal the box while the compound is still under pressure.

In testimony whereof I have signed my name to this specification.

ALFRED EDGAR WILSON. 

